National Dam Inspection Program. Hidden Lake Dam. (NDS ID Number PA-1136 DER-ID Number 40-228) Susquehanna River Basin, Hidden Lake Outlet, Luzerne County, Pennsylvania. Sherman Hoover. Phase I Inspection Report

摘要

Hidden Lake Dam is an earthfill dam, 550 feet long and 20 feet high. The crest width of the dam is 15 feet. The visible portion of the upstream slope was measured to be 1H:1V and the downstream slope was measured to be 1.5H:1V. No riprap protection was observed on the upstream slope. The spillway is located at the right abutment and consists of an overflow section 35 feet in length. The Hidden Lake Dam appears to be in poor condition. A slide was noted on the downstream slope approximately 240 feet from the left abutment. The slide appeared to be inactive. A wet area was noted to the left of the discharge end of the 15 ft. corrugated metal pipe drain line. Flow from the seepage area was determined to be less than 1 gallon per minute. The drain line for the dam consists of a 15 ft. corrugated metal pipe with the upstream portion of the pipe blocked. No adequate facilities exist to regulate the reservoir level. Based on the downstream potential for loss of life, the spillway design flood has been selected as the PMF. The spillway and reservoir are capable of controlling approximately 1% of the PMF without overtopping the embankment (low spot). Based on criteria established by the Corps of Engineers, the spillway is termed seriously inadequate. If Hidden Lake Dam would fail due to overtopping, the hazard potential for loss of life and property damage immediately downstream of the dam would be significantly increased from that which would exist just prior to the overtopping.